Synthflow

Voice agent infrastructure. Build a phone-agent in a weekend.

Production voice-agent platform — telephony, STT, LLM, TTS, and interrupt handling stitched together so you call an endpoint and get a working phone agent. Pluggable models at every layer.

Build, test, and deploy AI voice agents for phone calls.

A no-code platform for humanlike voice agents that handle inbound and outbound phone calls — receptionists, IVR, and outbound campaigns. It bundles telephony (SIP / Twilio), a proprietary turn-taking model for low-latency conversations, prompts, tools, and call analytics. Pay-as-you-go pricing with free starter credits.

Enterprise voice AI platform for automated phone calls.

An enterprise platform for building AI agents that handle inbound and outbound phone calls 24/7 with natural, real-time conversation. Bland bundles the language model, speech-to-text, text-to-speech, and telephony into a single per-minute rate, and integrates with tools like Twilio, Salesforce, HubSpot, and Zapier. Build agents in a web dashboard or via a REST API; a free tier lets you start before moving to usage-based paid tiers.

Lifelike enterprise voice AI agents for customer service calls.

PolyAI's Agentic Dialog Platform builds voice agents that resolve customer service calls for large enterprises in banking, healthcare, hospitality, telecom, and retail. Agent Studio gives non-technical teams a no-code builder while the ADK exposes developer APIs, with SOC 2, HIPAA, GDPR, and PCI DSS compliance built in. Its proprietary Raven model is trained on over a billion enterprise conversations.